Fluid pumping arrangement



Nov. 21, 1939. R, W, TIBBETTS 2,180,441

FLUID PUMPING ARRANGEMENT Filed oet. 14j-1957 Patented Nov. 2.1, 1939 UNITI- zo sTATjEs 2.180341: FLUID PUMPING 'ARRANGEMENT Raymond w. mum. cameos, mme, non. by mesne assignments, to stator Corporation, a

'corporation of Rhode Application October 14, 1937., Serial No.. 168,958

6 Claims. (Cl'. 32115) This invention relates to a drop tube assembly wherein globules or bodies offa liquid pump lighter uid bodies.. More particularly, this arrange'- ment maybe employed in conjunction with a 6. refrigerating system of the type disclosed -in .United States Patent No. 1,761,551, issued June 3, 1930, to Eastman A. Weaver, and United States Patent No. 1,892,869, issued January 3, 1933, to Daniel F. Comstock.V 'I'hese patents disclose re- 10 frigerating systems wherein a heavy propellant. having a relatively high boiling point pumps'a refrigerant vapor from an evaporator or cooler to a condenser by aspiration. Preferably such systems mayoperate at a low pressure; for example, the pressure in the cooler may be of the general order of four millimeters of mercury ab'- solute, so that there may be some tendency for gases to leak` into' the system. Furthermore,. under ycertain operating conditions, particularly 20, when an aqueous refrigerant is employed, such as water or water mixed with an anti-freeze ingredient. there is a tendency for certain gases to be received from the walls of the system even if the same is perfectly sealed against the leakage of atmospheric air.

Accordingly, as set forth in the above-identified Comstock patent, it is desirable to provide a' purger which is effective in compressing noncondensable gases and exhausting the same to the atmosphere. Such a purger as taught in that above-identified patent may conveniently comprise a drop tube in which successive bodies or globules of the propellant liquid, e. g., merury, entrain bodies of the non-condensable gases, compressing the same and'venting the same into a liquid-containing wellor vat. 'I'he liquid in this vat has its upper surface exposed to the atmosphere and the non-condensable gases may rise through the liquid to the atmosphere. 'thus 40 being exhausted.

The above-identiiled Comstock patent discloses an arrangement of the tubes and ducts associated with the purger' assembly which is satisfactory` and operative for the indicated purposes,

but. in a commercial refrigerating system, it is desirable to aiord a more compact assembly whichA may be more easily supported. For this purpose, the drop tube may be arranged concentrically within the return. ductJ through which the liquid propellant rises from the lower part of the purger assembly to a. spill-over connection from which the mercury is fed back to the boiler. Thus the drop tube is disposed within the outer duct and it is only necessary to afford supporting means for one tube orduct rather than two spaced ducts: Such an -arrangement alsoprotects the relatively small drop tube against injury from -accidental blows or the like.-

The arrangement ofthe return duct about the of Lyman E Whitney, such an arrangement l0v permits the purger tube. to be readily removed, if desired. It is also desirable to arrange the vat or well which. contains the liquid body of mercury that is exposed to the atmosphere so that this -well is disposed concentrically about 15 the lower end. of the drop tube and the lower end of the returnduct'. x y Such an assembly, while having distinct advantages from the point of view of manufacture and assembly, provides an arrangement which, 20 without further qualification, results in a tend.- ency of thefcompressed gases to lreturn to the low pressure portion of the system by rising in the return .duct rather than being exhausted to the atmosphere.

The present' invention aords' an air deec- -tor arranged about the lower end of the return duct to prevent sugli a short ciruiting oi` the gases, so that the ses bubbles may rise past the the spill-over. To permit the satisfactory arrangement of Such a detlector, the drop tube preferably may extend slightly below the lower 35 v'end ofthe return duct and the deiiector may be `in the form of a cup-like member securedto the lower extremity of the drop tube-v but spaced somewhat below` the lower end of the return duct, the side wall of this cup-like mem- 40 ber, however, being spaced outwardly from the lower end of the duct and extending .somewhat above its lower`v extremity. Thus gas. bubbles oi." bodies released from the d rop tube may rise about the lower part of the cup and may pass upward-v 45 ly between its outer wall andthe inner wall oi' the well, being directed by the-cup past the lower end of the return duct. On the' other hand, the lower extremity of the duct isspaced from the interior oi.' thecup so that mercury will readily 50 find its way intothe lower part. of the duct, from which the mercury may rise to the spill-over connection.

In the accompanying drawing:` Fig. l is' a diagrammatic view of a refrigerat- 55 ing system including a purger arrangement exempllfying the principles of this invention;

Fig. 2 is a broken, vertical, sectional view of the purger assembly; and

y Fig. 3 is a section on line 3-3 of Fig. 2.

The accompanying drawing, for purposes of illustration, shows a simple type of refrigerating system with which my purgerarrangement may be associated, it being understood that in practice this arrangement may be employed in more highly developed systems of the same general character, such, for example, as disclosed in the copending application Serial No. 171,325 of Lyman F. Whitney, filed October 27, 1937.

Such a system may comprise a boiler I which contains a body of liquid mercury and is provided with a heating element 2 such as an electrical resistance factor. A vapor duct or riser 3 extends upwardly from the boiler I to the aspirator nozzle 4 which is arranged to emit mercury vapor vat high velocity into a mixing chamber 5. The latter is connected by a vapor duct 6 to the upper part of an evaporator or cooler 1. yThis cooler contains a body of liquid refrigerant such as water or a suitable mixture of water and an anti-freeze agent. A funnel 8 is aligned with the nozzle 5 and is provided with suitable cooling means such. as fins I0.

The mercury vapor issuing from the nozzle 4 is effective in drawing refrigerant vapor from the cooler 1 through the duct 6, the mixed vapors passing into the funnel 8 Where the refrigerant vapor is compressed and the major portion of the propellant vapor is condensed. The refrigerant vapor rises through the duct I2 to the separating chamber I3, passing from the latter into the condenser coil I I where the refrigerant is condensed. The liquid refrigerant returns to the separating chamber I3 and passes into the drain I4, the lower end of which communicates with a mercury containing trap I5 connected by a duct I6` to the cooler 1. Thus as liquid refrigerant piles up in the pipe I4, the pressure on the mercury in trap I5 is suiiicient to cause some of the refrigerant to passthrough the trap and the pipe I6 back to the cooler. l

Some of the propellant vapor may stray into the refrigerant condenser, there being condensed and draining back to the trap I5 which is thus kept suitably filled with mercury. Excess niercury from the trap I5 passes through pipe I8 into the cooler 1. A trap 20 is connected to the lower part of this cooler receiving mercury therefrom so that when mercury fills this trap. it may overow into the duct 2I. The lower end of this duct isconnected to a downwardly inclined pipe or tube 22 which is joined to a standpipe 23. An

upper continuation 23a of the latter affords a drain to receive any condensed mercury which may appear in the mixing chamber 5.- Condensed propellant from the lower end of the funnel 8 is received by a drain 25 which forms one leg of a trap 26, the opposite leg 21 of which is arranged to emit liquid propellant into the chamber 29 at the upper part of tubular member Vu (Fig. 2).

A tube 3l 'is connected to the upper part of the condenser I4 to receive non-condensable gases therefrom and to direct the same into the chamber 23. :A drop tube 33 of restricted internal y diameter is disposed within the tubular member 2l, having its upper end flared outwardly, as

. designated by numeral 34, substantially to close the lower end of chamber 29 except for the opening provided by the upper end of the bore ot the Iduct 22. Accordingly, as

tube. The ared 'end 34 of tube 33 preferably `of the tube 33 permits the globules to act as liquidV pistons so that the successive bodies of gas are compressed as they approach the lower end of the tube.

A well or vat 35 is disposed about the? lower end of the drop tube 33 and contains a body of liquid mercury in which the lower end of the .tube and the lower end of the tubular member 30 are immersed. The upper part of the vat 35 may be open to the atmosphere, being, for eX- ample, connected to the tubular member 30 by radial struts 36 extending from a ring which has a firm frictional engagement with the member 30.

In accordance with this invention, a cup-like deilector 40 is secured to the lower end of the tube 33, the end of. this tube extending somewhat below the end of the tubular member 3l) and the cup-like member40 having a lower wall spaced above the lower extremity of the tube but below thelqwer extremity of the tubular member 30, while the side wall of the member 40 is spaced outwardly of the outer surface of the tubular member but extends upwardly above its lower extremity. as shown particularly in Fig. 2.

Since the surface of the body of 4liquid mercury in vat 35 is exposed to atmospheric pressure, this column will balance a higher column of mercury in the tubular member 30 which is the return duct through which mercury passes from the vat 35 to the spill-over connection with the end of the the mercury is received from the drop tube 33 bythe vat 35, the level of the mercury in the vat tends to rise, but since the surface of this mercury body is exposed to atmospheric pressure, the mercury is forced upwardly into the return duct 30. Mercury i'llls this duct until it reaches a level even with the connection withl pipe 22, whereupon the mercury will spill over into this pipe and thus be received by the standpipe 23. The latter contains a columrrof. liquid mercury which balances the boiler pressure and serves as a boiler feed pipe.

It is evident that the arrangement of the deilector 40 permits gas bubbles to pass upwardly about the end of the return duct afforded by tubular member 30 so that the gas does not passbaek into the system by rising through the mercury column in the duct 30. Accordingly the gasrises to the surface of the liquid body in vat 25 and is thus exhausted to the atmosphere. 0n the other hand, -sinc *the lower end cf the return duct is spaced'from the inner and lower walls oi' the defle'ctr 40, the mercury can pass between the' deflector and the lower end of the duct to enterlthe latter.

It is evident-filiali this invention permits a simple, compactfiiuiger assembly to be provided which maybeionvenlently supported and which may be conveniently assembled with' theother parts of a refrigerating system of the character disclosed herein.

While the present invention has particular utility when employed in conjunction with such a refrigerating system for removing non-condensing gases therefrom, it is evident that this arrangement may also be found advantageous invvarious liquid globules which are eii'ective in pumping lighter uid bodies.

I claim: A

1. In a system of the class described which contains circulating fluids, a purger for `exhausting non-condensable gases from the system, said purger including a drop tube of small diameter into the upperend of which successive liquid globules are fed to pump and compress bodies oi gas, the lower end of the tube having an outlet opening, an upwardly extending 'duct having an open lower end `iuxtaposed to the outlet opening, a receptacle surrounding the lower ends of `the tube and duct and containing a body of liquid in which the lower ends of the tube and duct are immersed, said' body of liquid having its surface exposed to the atmosphere, and a gas defiector secured to the lower end of the tube but being arranged to deect gas bodies from rising into the duct and thus returning to the system, whereby liquid may rise from saidvbody into the duct but gas may rise to the surface oi?- said liquid and be exhausted to the atmosphere.

,2. In a system of the class described which contains circulating ulds, a purger for exhausting non-condensable gases from' the system, said purger comprising a d rop tube of small diameter, the system being arranged to supply successive liquid globulesto the upper end of said tube to pump and compress bodies of gas, the lower end of the tube having an outlet opening, an .upwardly extending duct surrounding the tube and having an inlet opening at its lower end spaced above said outlet opening, a receptacle disposed about the lower ends of the tube and duct, said receptacle containing a body of liquid. in which the lower ends of the tube and duct are immersed, the surface oi' the liquid body being exposed to the atmosphere, and a gas deflector secured to wardly below the lower end of the duct, said deflector being arranged to deflect gas from the lower end of the duct, whereby liquid may rise in the duct while gas is deflected to rise in the liquid body and be exhausted to the atmosphere.

3. In a system of the class described Awhich contains circulating uids, a purger for exhausting non-condensable gases from the system, said purger comprising a drop tube of small diameter, the system being arranged to supply successive liquid globules to the upper end of said tube to pump and compress bodies offgas, the lower end of the tube having an outlet opening, an upwardly extending duct surrounding the tube and having an inlet opening spaced above said outlet opening, a receptacle disposed about the lower ends of the tube and duct, said receptacle containing a body of liquid in which the lower ends of the tube and duct are immersed. the surface of the liquid body being exposed to the .atmosphere, and a gas dellector secured to the lower end of the tube` above its outlet opening, said denector being of: cup-like form and having a'v lower wall below the lower end of the duct and thesidewall oithedeiieotorandtheoutersurthe lower end of the tube and extending outhaving a side wall disposed outwardly of thel t outer surface ofthe lower end of the duct. wherebyliquidiromthe liquidbody maypassbetween face of the lower end ci the duct and may rise into the duct while air is deflected from the lower end of the duct to rise in the liquid body and be exhausted to the atmosphere.

4. In a system of the class described which contains circulating fluids, a pumping assembLv including av drop tube pump in which successive liquid bodies entrain and pump bodies of a lighter fluid, a return duct surrounding the tube, a receptacle communicating with the lower parts of the tube and duct, said receptacle containing a body of the pumping liquid, the lower end oi' the tube extending below the lower end of thevdu'ct. said tube having an outlet opening below the duct, said duct having an inlet opening above the lower end of the tube, and a deiiector at theV lower fend of the tube to prevent the lighter iiuid from rising to said inlet opening, whereby the pumping liquid from 'said tubemay pass into the liquid body and liquid from the latter may pass into said duct, while the lighter fluid may rise to the surface of said liquid body.

5. In a system of the class described which contains circulating fluids, a pumping assembly comprising a drop tube in which successive liquid -bodies entrain and pump bodies of a liglter iluid,

a tubular member'surrounding said tube and extending above the same, an annular wall between the open upper end` oi the tube and the wall of the tubular member, ducts to supply the pumping liquid and the lighter iluid to the chamber provided in said tubular member above said wall, a receptacle at the lower end of the tube to receive the liquid and fluid therefrom, the

tubular member having an inlet opening through ,35

t which liquid may pass from said yreceptacle, a

deiector to prevent the lighter'uid it'o'm entering said inlet opening, and an outlet duct connected to said tubular member below the annular wall to receive liquid owing upwardly in said member, the lower part of the tubular member providing'a duct for the liquid and the upper part thereof' providing an inlet chamber for the drop tube.

6. In a system of the class described which contains circulating fluids, a pumping assembly including a drop tube pump in which successive liquid bodies entrain and pump bodies of a light er iiuid, a return duct surrounding the tube. a

receptacle communicating with the lower parts o0- of thetube and duct, said receptacle containing the tube being disposed below the lower end of the duct, said tube having an outlet openingwithin'fthe receptacle, said duct vhaving an in- 65 a body of the pumping liquid, the lower part of extending beneath the wall o! said duct and outwardly beyond the same to deiiect the lighter iiuid past the inlet, whereby the pumping 'liquid from-'said tube may pass into the liquid boch and liquid from the latter may lpass into said duct,while the lighter iluid may rise to the surme or ma nquid body. y

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